Apparatus for railway communication systems



A J. SORENSEN APPARATUS FOR RAILWAY COMMUNICATION SYSTEMS Filed Sept. 20, 1934 May 12, 1936.

4 2 a 7 M 2 W W m p g 6 7v 7 2 5 l f a w@ 5 21 w m k k A a u u no mm W Tm E Tm INVENTOR Andrew J Sorezzsem BY Q21 HLS' ATTORNEY Patented May 12, 1936 UNITED STATES PATENT I OFFICE APPARATUS FOR RAILWAY COMIMUNI- C'ATION SYSTEMS Application September 20, 1934, Serial No. 744,814

13 Claims.

My invention relates to apparatus for railway communication systems, and particularly to railway train telephone systems.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims. 7

It has been proposed in the United States application for Letters Patent, Serial No. 450,135,

filed May 6, 1930, by L. O. Grondahl, for Electric train signaling systems, to utilize the trafiic rails in multiple as the communication channel for transmitting a communication current between locations on two different trains, or between two spaced locations on the same train, or between a wayside station and a location on a train, the comunication current being preferably in the form of a modulated carrier current, such as, for example, a carrier telephone current.

At each location of such communication system a transmitting device and a receiving device are provided, together with an inductor adapted to be connected with either of said devices, and which inductor is disposed in inductive relation with the traffic rails. When the inductor of a location is connected with the transmitting device at the same location and comunication current supplied thereto, an electromotive force of a corresponding frequency is induced in the trafiic rails, and as a result of such electromotiv'e force, current flows in the rails in multiple in both directions from the point of induction and returns through the ground. When the inductor is connected with the receiving device at the same location it is effective to inductively receive an electromotive force in response to such communica tion current flowing in the rails.

It has been found that line wires and other conductors paralleling the traffic rails in which such communication current is induced, through their distributed capacity with ground and with the traflic rails and through their inductive relationship with the inductor, are also effective in carrying the communication current. That is to say, line wires and conductors paralleling the trafiic rails act in conjunction with the traflic rails to form a communication channel. I have found that at a distance equal to the length of the usual freight train from an inductor transmitting current, a line wire extending along the right-of-way may be carrying several times as much of the communication current as any one of the rails, notwithstanding the fact no apparatus for coupling such line wires and the rails is provided.

' It has also been proposed to mount the inducadvances.

tors on the vehicle of a train relatively high above the rails and in a plane to link a magnetic field transverse to the track in order to increase the inductance of the inductor to line wires extending along the right-of-way. v 7 I 7 Apparatus for cooperatively using line wires and the trafficrails as a communication channel is disclosed and claimed in a copending application for Letters Patent, Serial No. 696,663, filed November 4, 1933, by P. N. Bossart, for Railway communicating systems; and in a copending application for Letters Patent, Serial No. 72,605, filed April 3, 1936, by P. N. Bossart for Railway train communication systems. My present application may be considered as an improvement on the above cited Bossart applications.

A feature of my invention is the provision of apparatus for coupling one or more line wires to the traific rails at selected intervals to increase the amount of communication current that will flow in such line wires and thereby improve the operation of the communication system. A further feature of my invention is the provision of apparatus for coupling existing line wires with the trafiic rails in such a way that a low impedance path is provided for the communication current while the wayside circuits in which these line wires ordinarily form a part are undisturbed. To put it another way, a feature of my invention is the provision of apparatus operative to transfer communication current induced in the traffic rails to a line circuit near the location of the trans-, mitting inductor, carry such current along line Wires having relatively low impedance for the current, and then transfer the current from the line circuit back to the trafiic rails near the location of the receiving inductor. The line circuit Will be constantly effective notwithstanding the fact both the transmitting and receiving inductors may be mounted at the opposite ends of a train and hence move along the rails as the train Furthermore, the line circuit will be preferably made up of existing line Wires which form a part of existing circuits independent of the communication system.

In the accompanying drawing, Fig. 1 is a. diagrammatic view of one form of apparatus embodying my invention and wherewith the line wires which form a part of a wayside signal control circuit are coupled with the traflic rails at the junction of track sections commonly provided for a wayside signal system. Fig. 2 is a diagrammatic view of apparatus for coupling line wires used as a part of a telegraph circuit with the traffic rails at selected locations along theri htof-way, which apparatus also embodies my invention.

In each of the two views, like reference characters designate similar parts.

Referring to Fig. 1, the reference characters I and II designate the respective traflic rails of each of three railway tracks I, 2 and 3, over which tracks trafiic normally moves in the direction indicated by the arrows. Each of the tracks I, 2 and 3 is divided by insulated rail joints into track sections, such as are customarily provided for wayside signal systems. The associated wayside signal system is not shown in the drawing for the sake of simplicity since it may be of any of the standard types and since it constitutes no part of my present invention.

In this instance, only two complete track sections AB and B--C are shown for each of the tracks, and it will be understood that each of the three tracks will be divided into similar sections for the full lengthof a given stretch of the railway. The track sections A-B and B-C for the track-I are each provided with a track circuit which, in the case of section AB, consists of a source of current such as a battery I2 connected across the traffic rails I0 and I I at the outgoing end of the section, and a track relay designated by the reference character RA connected across the traffic rails at the entrance of the section. In like manner the track circuit for the section B-C includes a battery I2 connected across the rails at the right-hand end of the section and a relay RB connected across the rails at the left-hand end of the section. Each of the remaining tracksections will be provided with a similar track circuit. These track circuits controlover contacts operated by the track relay circuits used in'connection with the wayside signal system. For illustration, the track circuit for the section A-B- of track I' governs over a front contact I4 of its relay RA; an approach control circuit which consists of a battery I3 located at the left-hand; end of the section, two line wires WI and W2 extending the full length of the section-and a relay designated by the reference character 'VB' located at the right-hand end of the section. In like manner the track circuit for the section BC oftrack I governs a similar app-roach control circuit including a battery 22,. two line wires W3 and W4 and a relay Vc. Furthermore, each'of' the remaining track circuits associated with the successive sections for the track I will govern an approach control circuit similar to the control" circuits just described in connection with the sections A-B and B-C. These several approach control circuits will ordinarily govern apparatus inconnection with the wayside signal system, but the significant feature about such circuits in connection with the present invention is merely the'fact that the successive circuits pro vide a pair ofline wires which extend the full lengthof the track I, but which terminate at signal locations.

To combine the line wires of these approach 65 control circuits associated with the track I into a continuous circuit extending along a stretch of the railway, and which circuit may be utilized as a part of the communication channel for a train communication system independent of the wayside signal system without interfering in any way with their function in connection with the wayside signal system, I provide a transformer T and resistorsat each of several signal locations.

. At location A, a transformer TA consisting of three windings I4, I5 and I6, together with several resistors are provided. The winding I4 is interposed in the approach control circuit associated with the track section to the left of the location A by being connected between the winding of the relay VA and the line wire W5. The winding I5 of the transformer TA is interposed in the approach control circuit associated with the section AB by being connected between the battery I3 and the line wire W2. The winding I6 of the transformer TA has one terminal connected with a ground electrode I1 and its other terminal connected with the traffic rails of each of the three tracks I, 2 and 3, resistors I8 and I9 being interposed between the winding and the traffic rails of the track I, resistors 42 and 44 being interposed between the rails of the track 2 and the winding, and resistors 40 and 45 being interposed between the traffic rails of the track 3 and the winding, as will be readily understood by an inspection of Fig. 1. A resistor 2I is connected between the terminal. of the winding I4 adjacent the winding of the relay VA and the terminal of the winding I5 adjacent the battery I3. In other words, the transformer TA has three windings, one of which, I4, is connected in series with the VA relay at the same location, a second winding of which, I5, is connected in series with the line battery at the same location and the third winding of which, I6, is connected between the traffic rails of each of the different tracks and ground. At location B, a transformer TB and resistors are provided. Transformer TB consists of three windings 24, 25 and 26. The winding 24 is connected in series with the relay VB, the winding 25 is connected in series with the battery 22, while the winding-26 is connected between the ground electrode 2'! and the traffic rails over resistors, in a manner similar to that just described in connecting the windings of the transformer TA. A resistor 39 at-location B connects the two adjacent terminals of the windings 24 and 25 of transformer TB in the same manner the resistor 2I at location A connects the two windings I4 and I5 of the transformer TA. At location C a transformer To is provided, which has three windings 3I, 32 and 33 similar to the windings of the two transformers TA and TB. These windings of transformer T0 are connected with the approach control circuits and between the traific rails and ground in the same manner as described hereinabove in connection with the transformers TA and TB, and it is thought unnecessary to repeat their description in detail.

With the impedances of the first two windings of each of the transformers, that is, windings I4 and I5 of transformer TA, wind-ings 24 and 25 of transformer TB and windings BI and 32 of transformer T0, properly adjusted, and a proper selection of the resistors 2 I, 30 and 34, communication current will flow freely from one approach control circuit to the next by a line circuit which 7 is continuous for the full length of a given stretch of the railway. Starting with the line wire W6 at the left-hand end of Fig. 1, this continuous circuit can be traced over winding I4 of the trans' former TA, resistor 2|, winding I5, line wire W2, winding. 24 of transformerTB, resistor 30, winding 25, line wire W4, winding 3| of transformer T0, resistor .34, winding 32 and thence over the duced in the above-traced line circuit at any one of the transformers will flow from that transformer and return through the distributed capacities and ground.

The third winding of each of the transformers, that is, windings I6, 26 and 33 of the transformers TA, TB and To, respectively, is wound to give the proper transfer of communication current flowing from the traflic rails to ground to the abovetraced line circuit, or on the other hand to transfer such current flowing in the line circuit to the traflic rails. For example, communication current-flowing from the rails of track I over resistors I9 and I8, winding I6 of transformer TA and thence to ground at H, will induce electromotive forces in the windings I4 and I5 which will cause a corresponding current to flow in the line circuit including the line wires W6, W2, W4, etc., the return path for this latter current being completed through the distributed capacity of the line wires and ground. Again, communication current flowing in the windings I4 and I5 of transformer TA will induce an electromotive force in the Winding I6 which will set up a current that will flow to the rails of track I, through the distributed rail to ground resistance, and thence over ground electrode I! back to winding I6. Since the winding I6 is connected with the rails of tracks 2 and 3 in multiple with its connection with the rails of track I, it follows that a transfer of communication current from the rails of either track 2 or 3 to the line circuit will be accomplished in exactly the same manner as just described for track I. A transfer of communication current between the rails of tracks I, 2 or 3 and the line circuit will be accomplished in like manner at each of the other transformers TB and To. Hence, each of these transformers located at selected locations will be operative to '--transfer the communication current from the rails to the line circuit when a train-carried inductor transmitting current is in the vicinity of that transformer and will be operative to transfer the current from the line circuit back to the traffic rails in the vicinity of the inductor func- K represents a train occupying the track 2 and on the front end of which train an inductor 35 is mounted and on the rear end of which a second inductor 35 is mounted. Associated with each of these inductors 35 and 35 will be a transmitting device and a receiving dewlce of a com- -munication system such as referred to herein-' above, for two-way communication between these two spaced locations on the train K. Assuming the inductor 35 to be connected with its associated transmitting device for inducing an electromotive force in the traffic rails corresponding in frequency to the communication current supplied to such inductor, it is clear that current in response to such electromotive force will not only flow in the two rails in multiple from the point of induction and return over the ground path described in the above-mentioned Grondahl application, but such current will also flow along the traflic rails to the right and pass to ground over the path including resistor 3'1, resistor 38, winding 33 of the transformer T0 and the ground electrode 39, and thenGe'return to the rails of track 2 over electrode 21, winding 26 of transformer TB and resistors 50 and 5|, a portion of the. current, of course returning to the rails over the distributed rail to ground resistance. The effect of such current flowing in the winding 33 of transformer Tc will be to induce electromotive forces in the windings 3| and 32 of that transformer. That portion of the current flowing in the winding 26 of transformer TB will also induce electromotive forces in the windings 24 and 25 of that transformer. Since the windings 26 and 33 of transformers TB and T0 are reverse with respect to each other the electromotive forces induced in thewindings 24 and 25 of transformer TB and in the windings 3I and 32 of transformer To will add their effects and will set up a flow of communication current along the line wires W6, W2, W4 and W8, the return path being through the distributed capacities of the line wires and ground. Such communication current flowing in the windings I4 and I5 of transformer TA will induce an electromotive force in the winding I6, which will in turn set up a flow of current that passes to ground at I! on one side and will flow to ground on the other side over resistors 42 and 44, traffic rails of track 2 and the path including the third winding'of the transformer at the location next to the left of location A, a portion of the current of course flowing to ground through the distributed rail to'ground resistance of track 2 and also of the other tracks. This latter current flowing in the traffic rails of track 2 at the left of location A will be effective along with the communication current flowing in the rails of track 2 in accordance with the above-mentioned Grondahl application to induce an electromotive force in the inductor 36 at the rear end of the train, with the net result that the energy picked up by the inductor 36 for energizing the associated receiving device will be materially increased. It follows that communication current supplied to the rails through the medium of inductor 35 will be transferred to the line circuit in the vicinity of that inductor and will be transferred back to the rails at selected locations, the major portion in the vicinity of the receiving inductor 36.

At such'time as the inductor 36 is connected with its associated transmitting device to supply communication current to the traflic rails, such current will flow to ground at I! over the path including winding I6 of transformer TA to induce electromotive forces in windings I4 and I5 and communication current will be set up in the line circuit which will travel along the line wires W2, W4 and W8. This current will now induce an electromotive force in the winding 26 of transformer TB and in the winding 33 of transformer To which in turn will cause current to flow to the rails of track 2 and efiectively influence the erated by direct current whereas the communication current is of relatively high frequency.

Furthermore, it is clear that current from a line battery such as the battery 22 will not flow to theapproach control circuits adjacent its own circuit.

The above-traced line circuit including the line wires W6, W2, W4 and W8 will function to transmit communication current in connection with the tracks I and 3, since the third winding of each sistors. It will be clear that another control ciricuit associated with the wayside, signal system for the tracks 2 and 3 may also be made to function in connection with transmitting the communication current should it seem'desirableto do so.

A great advantage in using wayside signal circuits such as shown in Fig. l, isthatthese circuits always terminate in instrument cabinets along the right-of-way and no long runs of wire are necessary. If such wayside signal circuits are not available, it is feasible, however, to use a pair of telegraph wires belonging to the same circuit. In Fig. 2, the wires W9 and WIO designate two line wires of a telegraph circuit extending along the railway tracks I, 2 and 3. In this instance, the transformer TA provided at the location A has its first winding. l4 interposed in the line wire Will and its second winding 15 interposed in the line wire W9 while its third winding 7 I6 is connected between the ground I! and the traffic rails of the tracks I 2 and 3 in exactly the same manner as in Fig. 1. In this case, the windings l4 and I5 are so disposed that current flowing in therespective line wires W9 and WH] in opposite directions, such as the telegraph 'current, will create fluxes that cancel each'other. Consequently, a current flowing in the samedirection in both wires and hence in both windings- I4 and i5 will create fluxes that are additive, and

will induce an electromotive force in the winding 16 which will set up a current flowing between the ground and the traflic rails of the several tracks. Again, communication current flowing from the rails to the ground throughthe'winding l6 will be effective to create electromotive forces in the windings l4 and 15 which will cause a current to flow in the two wires W9 and Will in multiple. The transformer Ts provided at location B has its three windings 24, 25 and. 26 connected with the line wires W9 and WI!) and with the traffic rails in exactly the same manner as just described in connection with the transformer TA of Fig. 2. It willbe seen, therefore,.that the line wires W9 and W19 will function to transmit communication current along the tracks I, 2 and 3. in the same manner as the line circuit of Fig. 1. That is to say, the line wires W9 and Will of Fig.

.2 function to transmit communication current without interference with the telegraph circuitof which they originally form a part.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:-

1. In combination, a railway track, a train to travel on said track, means located on the train or inducing a communication current in the traffic rails of said track, a line'wire extending along the track, a transformer including a first winding interposed in said linewire, a circuit connected rent flowing from rails to ground to induce an electromotive force in said first winding for causing such communication current to flow in the line wire in both directions from said transformer and return through the ground, and signaling means governed by such current flowing in said line wire. 2.. In combination, a railway track, a train to travel on said track, means located on the train for inducing a communication current in the trafiicrails of said track, a line wire extending along said track to form one side of a control circuit receiving current from a particular source, a transformer including a first winding interpose in said line wire, circuit means connected oetween the rails and ground and including a second winding of said transformer, said circuit means operative in response to the communication current flowing from the rails to ground to induce an electromotive force in said first winding for causing-such "communication current to flow in the line wire in both directions from the transformer independent of said particular source, and

signaling means governed by such communication current flowing in said line wire.

3. In combination, a railway track, a train to travel on said track, means located on the train for inducing a communication current in the traffic rails of said track, a line wire extending along said track to form one side of a control circuit receiving current from a particular source, a transformer including a first winding interposed in said line wire, circuit means connected between the rails and ground and including a second winding of said transformer, said circuit U means operative in response to the communication current flowing from the rails to ground to induce an electromotive force in said first winding for causing such communication current to flow in the line wire independent of said particular source over a circuit including the line wire on. each side of the transformer and the distributed' capacitance between such wire and ground, and signaling means governed by such communication current fiowing in said line wire.

4. In combination, a railway track, a line wire parallel to the track and adapted to form one side of a circuit receiving current-from a particular source, a transformer including a first winding interposed in said line wire, and a circuit connected between the traffic rails of said track and ground and including a second winding of said transformer and said circuit operative in response to a communication current flowing from the rails to ground to induce an electromotive force in. said first winding for causing communication current to flow in the line wire in both directions from the transformer independent of said particular source and to inductively receive electromotive force in response to communication current flowing in the line wire for supplying such communication current to the traffic rails.

5. In combination, a railway track, a pair of line wires parallel to said track and adapted to form the two sides of a circuit receiving current from a particular source, a transformer including a first winding interposed in one of said line wires and a second winding interposed'in the other of said line wires, and a circuit connected between the trafiic rails of said track and ground and including a third winding of said transformer and rent flowing from the rails to ground to induce electromotive forces in said first and second windings effective to cause such communication current to flow in said line wires in multiple independent of the current supplied by said particular source.

6. In combination, a railway track, a line wire extending along said track, a plurality of trans formers spaced apart along the track and each including a first winding interposed in said line wire, and a plurality of circuit means connected between the rails of the track and ground one at each transformer and including a. second winding of the respective transformer, each of said circuit means operative in response to a communication current flowing from the rails to ground to induce an electromotive force inthe first winding of the respective transformer to cause such current to flow in said line wire in both directions from that transformer and to inductively receive electromotive force in response to such communication current flowing in the line wire, whereby the communication current is transferred from the rails to the line wire at one location and is transferred back to the rails from the line wire at a second location.

7. In combination, a railway track, a pair of line wires parallel to said track and adapted to form the two sides of a control circuit receiving current from a particular source, a plurality of transformers spaced apart along the track and each including a first winding interposed in one of said line wires and a second winding interposed in the other of said line wires, a plurality of circuit means connected between the rails of said track and ground one at each transformer and including a third winding of the respective transformer, each of said circuit means operative in response toa communication current flowing from the rails to ground to induce electromotive forces in said first and second windings of the respective transformer to cause such current to flow in said line wires in multiple independent of said particular source and to inductively receive electromotive forces in response to such communication current flowing in said line wires, whereby communication current is transferred from the rails to the line wires at one location and transferred back to the rails from the line wires at a second location independent of the control circuit.

8. In combination, a railway track, a plurality of control circuits located successively along the track, each of said circuits including a line wire extending along said track, a transformer located at each junction of said successive circuits and including a first winding interposed in the line wire of the circuit to the right of the junction and a second winding interposed in the line wire of the circuit to the left of the junction, a resistor at each junction connected between the two adjacent terminals of the first and second windings of the transformer at the same junction, and a circuit at each junction connected between the rails of said track and ground and including a third winding of the transformer and operative in response to a communication current flowing from the rails to ground to induce electromotive forces in the first and second windings of that transformer for causing such communication current to flow along the line wires of the successive circuits.

9. In combination, a railway track, a train to travel on said track, communication means at each of two spaced locations on the train each operative to induce communication current in the rails or to inductively receive such current in response to communication current flowing in the rails, a line wire extending along the railway, a plurality of transformers disposed along the track and each including a first winding interposed in said line wire, and a circuit means at each transformer connected between the rails and ground and including a second winding of the respective transformer, whereby communication current induced in the rails at one location of the train will be transferred to the line wire at the transformers relatively close to that location on the train and will be transferred back to the rails from the line wire at the transformer relatively close to the second train location.

10. In combination, a railway track, a train to travel on said track, communication means at each of two spaced locations on the train each operative to induce communication current in the rails or to inductively receive such current in response to communication current flowing in the rails, a plurality of control circuits located successively along said track, each of said circuits including a line wire extending along the track, a transformer located at each junction of said successive circuits and including a first winding interposed in the line wire of the circuit to the right of the junction and a second winding interposed in the line wire of the circuit to the left of the junction, a resistor at each junction connected between the two adjacent terminals of the first and second windings of the transformer at the same junction, and a circuit at each junction connected between the rails and ground and including a third winding of the transformer whereby communication current induced in the rails at one location of the train will be transferred to the line wires of the control circuits, transmitted along the line wires of the successive circuits and then transferred back to the rails for influencing the communication means at the second location on the train.

11. In combination, a railway track insulated in track sections, a train to travel on said track, communication means at each of two spaced locations on the train each operative to induce communication current in the rails or to inductively receive such current in response to communication current flowing in the rails, a control circuit for each section including a pair of line wires and an individual current source, a transformer at each junction of such track sections including a first winding interposed in the control circuit to the right of the junction and a second winding interposed in the circuit to the left of the junction, a resistor at each junction connected between said first and second windings of the transformer at the same junction; and circuit means at each of such junctions including a resistor connected from the rails of one section to the rails of the next section, a, third winding of the transformer at the same junction and ground; whereby communication current induced in the rails of one section by the means at one location on the train. will be transferred to the line wires of the control circuit of that location, transmitted along the control circuits independent of the individual current sources and transferred back to the rails of another section from the line wires for influencing the means at the other location on the train.

12. In combination, a railway including a plurality of tracks each of which is insulated into track sections, a train adapted to travel on said tracks, communication means at each of two spaced locations on the train each operative to supply communication current in the rails or to receive such current in response to communicaf track section s including a first 'windingjnterposed inithe line wire to the right t of the junction and a second winding interposed in the line wire to the left of the junction, a resistor at each junction connected between said first and second windings of the transformer at ,the same junction, a third winding of each trans- A former each of which has one terminal grounded, ,anda plurality of parallel circuits at each junction for connecting the other terminal of the third winding of the transformer at the same junction with thetrafiic rails of each of said tracks, whereby communication current supplied in the rails' of a section of any one of said tracks will be transferred to the line wires of the control circuits-and transferred back to the rails of another section of the same track.

13. In combination; a railway including a plurality of tracks, a train adapted to travel on said tracks, communication means at each of two spaced locations on the train each operative to terposed in said line wire, and a second winding.

for each transformer having one terminal grounded, and its other terminal connected with the traflic rails of the different tracks in parallel, whereby communication current induced in the rails of any one of said tracks will be transferred" to the line wire in the vicinity of the point of induction and transferred ba'ck'to the rails at a remote point.

ANDREW J. SORENSEN. 

